The medical body area network (MBAN) system has been devised to provide a flexible platform for wireless networking of multiple sensors used for monitoring a patient's physiological data in a healthcare facility, such as a hospital.
The MBAN system operates in a band of 2360 MHz to 240 MHz based on IEEE 802.15.4 and its maximum emission bandwidth is restricted to 5 MHz.
The transmission power of the MBAN system, when operating in 2360 to 2390 MHz, has the smaller one of 1 mW and 10*log(B) dBm. At this time, B is 20 dB emission bandwidth. When operating in 230 to 2400 MHz, the MBAN system uses the smaller value of 20 mW and 10*log(B) dBm as its transmission power. At this time, B is 20 dB emission bandwidth.
2360 to 2400 MHz is a frequency band allocated for another wireless communication system, and the MBAN system operates based on wireless recognition technology. This wireless recognition technology refers to a communication technology in which a network or wireless communication apparatus actively senses and determines the ambient communication environment to adaptively vary transmission/reception characteristics, such as frequency band, transmission power, and encoding scheme, for the optimal communication. At this time, the wireless recognition apparatus, upon sensing the use of other licensed users or primary users in the frequency band the device intends to use, is operated not to interfere with the communication of the other users, among others.
For such purpose, in the MBAN, in the case of operation in a band of 2360 to 2390 MHz, MBAN apparatuses operate in a registered healthcare facility, in principle. In other words, the use of 2360 to 230 MHz should be controlled in cooperation with other licensed users, and when the other licensed users use the corresponding band, all the operations should be initialized in this band, and the operations should be resumed by newly using a band of 2390 to 2400 MHz.
When the MBAN apparatuses move to the outside, their operation should be stopped or their transmission band needs to be changed to a band of 2390 to 2400 MHz that is used as a basic band before transmission. When operating in 2390 to 2400 MHz, the MBAN apparatuses may be used without a limitation on whether it is located indoors or outdoors.
In the conventional MBAN system, a definition has been yet to be made on a method of switching a channel used in one of the 2360 to 2390 MHz band and the 2390 to 2400 MHz band to the other band when the above-described situation occurs.